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| 1 | +%% This Source Code Form is subject to the terms of the Mozilla Public |
| 2 | +%% License, v. 2.0. If a copy of the MPL was not distributed with this |
| 3 | +%% file, You can obtain one at https://mozilla.org/MPL/2.0/. |
| 4 | +%% |
| 5 | +%% Copyright (c) 2007-2023 VMware, Inc. or its affiliates. All rights reserved. |
| 6 | +%% |
| 7 | + |
| 8 | +-module(rabbit_queue_member_eval). |
| 9 | + |
| 10 | +-feature(maybe_expr, enable). |
| 11 | + |
| 12 | +-behaviour(gen_server). |
| 13 | + |
| 14 | +-export([on_node_up/1, on_node_down/1]). |
| 15 | + |
| 16 | +-export([start_link/0]). |
| 17 | + |
| 18 | +%% gen_server callbacks |
| 19 | +-export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, |
| 20 | + code_change/3]). |
| 21 | + |
| 22 | +-define(SERVER, ?MODULE). |
| 23 | +-define(DEFAULT_INTERVAL, 60000*60). |
| 24 | +-define(SHORT_INTERVAL, 10000). |
| 25 | + |
| 26 | +-define(EVAL_MSG, member_eval). |
| 27 | + |
| 28 | +-record(state, {timer_ref :: reference(), |
| 29 | + default_interval :: non_neg_integer(), |
| 30 | + short_interval :: non_neg_integer(), |
| 31 | + target_group_size :: non_neg_integer() | undefined}). |
| 32 | + |
| 33 | +%%---------------------------------------------------------------------------- |
| 34 | +%% Start |
| 35 | +%%---------------------------------------------------------------------------- |
| 36 | + |
| 37 | +-spec start_link() -> rabbit_types:ok_pid_or_error(). |
| 38 | +start_link() -> gen_server:start_link({local, ?SERVER}, ?MODULE, [], []). |
| 39 | + |
| 40 | +%%---------------------------------------------------------------------------- |
| 41 | +%% API |
| 42 | +%%---------------------------------------------------------------------------- |
| 43 | + |
| 44 | +on_node_up(_Node) -> |
| 45 | + gen_server:cast(?SERVER, nodechange). |
| 46 | + |
| 47 | +on_node_down(_Node) -> |
| 48 | + gen_server:cast(?SERVER, nodechange). |
| 49 | + |
| 50 | +%%---------------------------------------------------------------------------- |
| 51 | +%% gen_server callbacks |
| 52 | +%%---------------------------------------------------------------------------- |
| 53 | + |
| 54 | +init([]) -> |
| 55 | + DefaultInterval = rabbit_misc:get_env(rabbit, member_eval_default_timeout, |
| 56 | + ?DEFAULT_INTERVAL), |
| 57 | + ShortInterval = rabbit_misc:get_env(rabbit, member_eval_short_timeout, |
| 58 | + ?SHORT_INTERVAL), |
| 59 | + TargetGroupSize = rabbit_misc:get_env(rabbit, member_eval_target_group_size, |
| 60 | + undefined), |
| 61 | + Ref = erlang:send_after(DefaultInterval, self(), ?EVAL_MSG), |
| 62 | + {ok, #state{timer_ref = Ref, |
| 63 | + default_interval = DefaultInterval, |
| 64 | + short_interval = ShortInterval, |
| 65 | + target_group_size = TargetGroupSize}}. |
| 66 | + |
| 67 | +handle_call(_Request, _From, State) -> |
| 68 | + {reply, ok, State}. |
| 69 | + |
| 70 | +handle_cast(nodechange, #state{timer_ref = OldRef, |
| 71 | + short_interval = Time} = State) -> |
| 72 | + _ = erlang:cancel_timer(OldRef), |
| 73 | + Ref = erlang:send_after(Time, self(), ?EVAL_MSG), |
| 74 | + {noreply, State#state{timer_ref = Ref}}; |
| 75 | +handle_cast(_Msg, State) -> |
| 76 | + {noreply, State}. |
| 77 | + |
| 78 | +handle_info(?EVAL_MSG, #state{default_interval = DefaultInterval, |
| 79 | + short_interval = ShortInterval, |
| 80 | + target_group_size = TargetSize} = State) -> |
| 81 | + Res = eval_quroum_queue_membership(TargetSize), |
| 82 | + NewTimeout = case Res of |
| 83 | + noop -> |
| 84 | + DefaultInterval; |
| 85 | + _ -> |
| 86 | + ShortInterval |
| 87 | + end, |
| 88 | + Ref = erlang:send_after(NewTimeout, self(), ?EVAL_MSG), |
| 89 | + {noreply, State#state{timer_ref = Ref}}; |
| 90 | +handle_info(_Info, State) -> |
| 91 | + {noreply, State}. |
| 92 | + |
| 93 | +terminate(_Reason, _State) -> |
| 94 | + ok. |
| 95 | + |
| 96 | +code_change(_OldVsn, State, _Extra) -> |
| 97 | + {ok, State}. |
| 98 | + |
| 99 | +%%---------------------------------------------------------------------------- |
| 100 | +%% Internal functions |
| 101 | +%%---------------------------------------------------------------------------- |
| 102 | + |
| 103 | +eval_quroum_queue_membership(TargetSize) -> |
| 104 | + LocalLeaders = rabbit_amqqueue:list_local_leaders(), |
| 105 | + ExpectedNodes = rabbit_nodes:list_members(), |
| 106 | + Running = rabbit_nodes:list_running(), |
| 107 | + eval_quorum_members(ExpectedNodes, Running, LocalLeaders, TargetSize, noop). |
| 108 | + |
| 109 | +eval_quorum_members(_ExpectedNodes, _Running, [], _TargetSize, Result) -> |
| 110 | + Result; |
| 111 | +eval_quorum_members(ExpectedNodes, Running, [Q | LocalLeaders], TargetSize, OldResult) -> |
| 112 | + {ok, Members, {_, LeaderNode}} = ra:members(amqqueue:get_pid(Q)), |
| 113 | + |
| 114 | + %% Check if Leader is indeed this node |
| 115 | + Result = case LeaderNode =:= node() of |
| 116 | + true -> |
| 117 | + MemberNodes = [Node || {_, Node} <- Members], |
| 118 | + Remove = MemberNodes -- ExpectedNodes, |
| 119 | + case Remove of |
| 120 | + [] -> |
| 121 | + add_member(Q, Running, MemberNodes, TargetSize); |
| 122 | + _ -> |
| 123 | + remove_members(Q, Remove) |
| 124 | + end; |
| 125 | + false -> |
| 126 | + noop |
| 127 | + end, |
| 128 | + eval_quorum_members(ExpectedNodes, Running, LocalLeaders, TargetSize, |
| 129 | + update_result(OldResult, Result)). |
| 130 | + |
| 131 | +add_member(Q, Running, MemberNodes, TargetSize) -> |
| 132 | + New = Running -- MemberNodes, |
| 133 | + case should_add_node(MemberNodes, New, Q, TargetSize) of |
| 134 | + true -> |
| 135 | + %% In the future, sort the list of new nodes based on load, |
| 136 | + %% availability zones etc |
| 137 | + Node = hd(New), |
| 138 | + QName = amqqueue:get_name(Q), |
| 139 | + case rabbit_quorum_queue:add_member(Q, Node) of |
| 140 | + ok -> |
| 141 | + rabbit_log:debug( |
| 142 | + "Added node ~ts as a member to queue ~ts as " |
| 143 | + "the queues target group size is not met and " |
| 144 | + "there are enough nodes in the cluster", [Node, QName]); |
| 145 | + {error, Err} -> |
| 146 | + rabbit_log:warning( |
| 147 | + "~ts: failed to add member (replica) on node ~w, error: ~w", |
| 148 | + [rabbit_misc:rs(QName), Node, Err]) |
| 149 | + end, |
| 150 | + ok; |
| 151 | + false -> |
| 152 | + noop |
| 153 | + end. |
| 154 | + |
| 155 | +should_add_node(MemberNodes, New, Q, TargetSize) -> |
| 156 | + CurrentSize = length(MemberNodes), |
| 157 | + TargetSize = get_target_size(Q, TargetSize), |
| 158 | + maybe |
| 159 | + true ?= CurrentSize < TargetSize, %% Target size not reached |
| 160 | + true ?= (TargetSize - CurrentSize) =< length(New), %% Enough nodes, |
| 161 | + true ?= rabbit_nodes:is_running(lists:delete(node(), MemberNodes)), |
| 162 | + true ?= are_members_up_to_date(MemberNodes, Q) |
| 163 | + end. |
| 164 | + |
| 165 | +are_members_up_to_date(_MemberNodes, _Q) -> |
| 166 | + %% _RaMetrics = erpc:multicall(lists:delete(node(), MemberNodes), |
| 167 | + %% ets, |
| 168 | + %% lookup, |
| 169 | + %% [ra_metrics, amqqueue:get_name(Q)], 10000), |
| 170 | + %% _LocalMetric = ets:lookup(ra_metrics, amqqueue:get_name(Q)), |
| 171 | + %% Do something with the result |
| 172 | + true. |
| 173 | + |
| 174 | +get_target_size(Q, undefined) -> |
| 175 | + get_target_size(Q); |
| 176 | +get_target_size(_Q, N) when N > 0 -> |
| 177 | + N. |
| 178 | + |
| 179 | +get_target_size(Q) -> |
| 180 | + case rabbit_policy:get(<<"target-group-size">>, Q) of |
| 181 | + undefined -> |
| 182 | + 0; |
| 183 | + N -> |
| 184 | + N |
| 185 | + end. |
| 186 | + |
| 187 | +remove_members(_Q, []) -> |
| 188 | + ok; |
| 189 | +remove_members(Q, [Node | Nodes]) -> |
| 190 | + case rabbit_quorum_queue:delete_member(Q, Node) of |
| 191 | + ok -> |
| 192 | + ok; |
| 193 | + {error, Err} -> |
| 194 | + QName = amqqueue:get_name(Q), |
| 195 | + rabbit_log:warning("~ts: failed to remove member (replica) on node " |
| 196 | + "~w, error: ~w", |
| 197 | + [rabbit_misc:rs(QName), Node, Err]) |
| 198 | + end, |
| 199 | + remove_members(Q, Nodes). |
| 200 | + |
| 201 | + |
| 202 | +%% Make sure any non-noop result is stored. |
| 203 | +update_result(noop, Result) -> |
| 204 | + Result; |
| 205 | +update_result(Result, noop) -> |
| 206 | + Result. |
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